The disquisition introduced the whole bag of tricks to the drew line cement pole measured groundwork pit,through used skin ruler,and go along analysis interrelated concept,its feasibility and safety proceeding.

This paper maily expourds the effect of material amount on pit class,proposes the method and the suggestion for solving the size of coal reducing.

In this paper,the authors have established the numerical simulations to analyze the intensification of the turbulence and the changement of compression wave by branching tunnel perturbation and have compared the result of numerical simulation with the experiment.